Theory: The Fire Familiar is built for quick kills, Guardian Angel (GA) and Antimagic Field (AMF) kill it quickly. Using Dispel Magic (DM) will nullify GA, using lots of AS will help you survive longer against AMF. Having a Wall/Tank in front gives the FF more rounds to do its work against most teams.

Application: Grow a single minion to about 100K MPR with a FF anyway you can. When you reach 100K MPR train AS on your large minion and hire a second minion for DM purposes. Continue with two minions until at least 200K MPR. At 200K MPR add a Third minion that will be a Heavy Tank, add as much High AC armor as you can find and Decent weapons (A Mage Shield (MgS) could be a nice addition).

Variation 1: Don't use a wall, just gut it out with DM and AS.

Variation 2: Add Enchant defense spells to the DM enchanter (GA is a good choice).